Angular dependence of the Wigner time delay upon strong field ionization from an aligned p-orbital

TL;DR

This study investigates how the Wigner time delay in strong-field ionization varies with electron emission direction from an aligned p-orbital, revealing a significant angular dependence and confirming theoretical predictions.

Contribution

It provides experimental evidence of angular dependence of Wigner time delay in strong-field ionization from an aligned p-orbital, supported by theoretical modeling.

Findings

Wigner time delay varies by over 400 attoseconds with emission angle.

Time delay is independent of dimer-cation parity.

Experimental results agree with theoretical models.

Abstract

We present experimental data on the strong-field ionization of the argon dimer in a co-rotating two-color (CoRTC) laser field. We observe a sub-cycle interference pattern in the photoelectron momentum distribution and infer the Wigner time delay using holographic angular streaking of electrons (HASE). We find that the Wigner time delay varies by more than 400 attoseconds as a function of the electron emission direction with respect to the molecular axis. The measured time delay is found to be independent of the parity of the dimer-cation and is in good agreement with our theoretical model based on the ionization of an aligned atomic p-orbital.